A wire braking method and a braking system in a dual mode

Abstract

The present invention discloses a dual-mode brake-by-wire method and braking system, which belongs to the field of automobile braking and includes a pedal assembly, a vehicle controller electrically connected to the pedal assembly, and a brake-by-wire module electrically connected to the vehicle controller. The brake-by-wire module adopts a redundant structure and includes a main brake-by-wire unit and a redundant brake-by-wire unit. Both the main brake-by-wire unit and the redundant brake-by-wire unit are connected to the brake caliper via a brake connector. The above-mentioned dual-mode brake-by-wire method and braking system significantly improve the reliability, safety, and response accuracy of the brake-by-wire system through the redundant acquisition of braking intentions by dual sensors, the backup of dual brake-by-wire units, and the intelligent switching flow path of the brake connector, ensuring the stable and efficient operation of the braking function under complex working conditions, thereby being applicable to both normal driving mode and automatic driving mode.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile braking, and in particular to a dual-mode wire control braking method and a braking system. Background Art

[0002] With the advancement of automotive electrification and intelligent technology, drive-by-wire systems are gradually replacing traditional mechanical control systems. These systems replace mechanical connections by transmitting the driver's operating intentions or autonomous driving signals to actuators in the form of electrical signals through sensors and electronic control units (ECUs), enabling precise control of the vehicle's steering, acceleration, and braking. As a core actuator, the brake-by-wire system significantly improves driving safety by adjusting brake response speed and braking force in real time. Its integrated brake energy recovery function effectively extends the range of electric vehicles, making it a key component in electric vehicles, hybrid vehicles, and autonomous vehicles.

[0003] Typical technical solutions of existing wire control brake systems are as follows:

[0004] 1. Signal transmission: A single sensor (such as an angle sensor or force sensor) captures the driver's braking intention (pedal travel or pedal force), processes it in the ECU, and sends it to the hydraulic control unit (HCU). This drives the motor to build pressure, which is then transmitted through the brake lines to the caliper for braking. This approach carries the risk of sensor failure leading to brake signal interruption.

[0005] 2. Structural composition: (1) A single brake unit design is usually used, lacking redundant backup. If the HCU or motor fails, it may cause the entire vehicle's brakes to fail, which is a major safety hazard, especially in autonomous driving scenarios. (2) NVH (noise, vibration, and harshness) performance defects: The traditional pedal structure uses a fixed spring design, which is prone to noise due to mechanical vibration during braking and cannot effectively buffer the driver's pedaling impact, affecting driving comfort. (3) Limited layout flexibility: Existing wire control brake systems are mostly integrated structures that need to be fixedly installed in a specific position in the front cabin of the vehicle. They are difficult to adapt to the cabin space differences of different models (such as compact cars and SUVs), increasing the complexity and cost of the entire vehicle design. Summary of the Invention

[0006] The purpose of the present invention is to provide a dual-mode wire control braking method and braking system to solve the above technical problems.

[0007] To achieve the above object, the present invention provides a dual-mode brake-by-wire method, comprising the following steps:

[0008] S1. Determining the driver's braking intention and braking force in a normal driving mode or an automatic driving mode, generating a braking command, and transmitting the control command to a brake-by-wire module;

[0009] In step S1, in normal driving mode, when the angle sensor collects the rotation angle of the pedal arm Or the force sensor synchronously collects the pedaling force When it is greater than 0, it is determined that there is a braking intention, and when the rotation angle is set and pedaling force When the signals are primary and auxiliary respectively, the braking force is calculated using the following formula:

[0010] (1);

[0011] Where, Indicates the travel-braking force coefficient; Indicates the angle-stroke conversion coefficient;

[0012] When setting the pedaling force and rotation angle When the signals are main and auxiliary respectively, the braking force is calculated using the following formula :

[0013] (2);

[0014] Where, Indicates the piston area of the brake master cylinder;

[0015] In autonomous driving mode, the vehicle's front environment is monitored in real time through onboard sensors to identify obstacles or the distance to the vehicle in front. , set the minimum safety distance to ,when When the braking intention is determined, the braking force is calculated using the following formula :

[0016] (3);

[0017] Where, Indicates the vehicle mass; and Respectively represent the real-time vehicle speed and the relative speed between the current vehicle and the obstacle or the vehicle in front;

[0018] S2. The ECU component of the brake-by-wire module obtains the brake pressure according to the received brake command;

[0019] The S3 and HCU components transfer the brake fluid in the reservoir to the brake calipers to perform braking.

[0020] Preferably, step S2 specifically includes the following steps:

[0021] S21. Consider the piston area of the brake caliper , calculate brake pressure :

[0022] (4);

[0023] S22. Calculate motor torque based on HCU component efficiency :

[0024] (5);

[0025] Where, Indicates the piston area of the HCU assembly; Indicates the length of the transmission arm of the HCU assembly;

[0026] And add motor speed constraints:

[0027] (6);

[0028] Where, Indicates the maximum speed of the motor; Indicates the maximum linear velocity of the piston of the HCU assembly; Indicates the transmission ratio of the HCU assembly; Indicates the motor rotor radius.

[0029] Preferably, in step S3, when the main brake-by-wire unit fails, the brake connector is used to switch to the redundant brake-by-wire unit for control, and to compensate for the pipeline pressure loss:

[0030] (7);

[0031] in,

[0032] (8);

[0033] Where, Indicates compensation pressure; Indicates the pressure value of loss; Indicates the friction coefficient between the brake fluid and the pipeline; Indicates the length of the pipeline; Indicates the pipe diameter; Indicates the density of brake fluid; Indicates brake fluid velocity.

[0034] Preferably, in step S3, the brake fluid pressure of the HCU component is collected in real time and fed back to the ECU component. The ECU component adjusts the motor torque through a PID algorithm according to the fed-back brake fluid pressure to form a closed-loop control.

[0035] A braking system for executing a dual-mode brake-by-wire method includes a pedal assembly, a vehicle controller electrically connected to the pedal assembly, and a brake-by-wire module electrically connected to the vehicle controller. The brake-by-wire module adopts a redundant structure and includes a main brake-by-wire unit and a redundant brake-by-wire unit. Both the main brake-by-wire unit and the redundant brake-by-wire unit are connected to the brake caliper via a brake connector.

[0036] Preferably, the pedal assembly includes a mounting shell arranged on the firewall of the vehicle and a pedal arm with one end rotatably arranged inside the mounting shell, and the other end of the pedal arm extends out of the mounting shell and is fixedly connected to the brake pedal;

[0037] An angle sensor is provided at the rotational connection between the pedal arm and the mounting housing, and a force sensor is provided at the power output end of the pedal arm via an elastic buffer assembly. Both the force sensor and the angle sensor are electrically connected to the output end of the vehicle controller. The vehicle controller determines the driver's braking intention and braking force based on the collected values of the force sensor and the angle sensor.

[0038] The force sensor and angle sensor serve as backup for each other.

[0039] Preferably, the primary brake-by-wire unit and the redundant brake-by-wire unit each include a fluid reservoir, an HCU component connected to an output end of the fluid reservoir, and an ECU component electrically connected to the HCU component. The ECU component of the primary brake-by-wire unit and the ECU component of the redundant brake-by-wire unit communicate with each other to achieve bidirectional backup.

[0040] The ECU component is electrically connected to the vehicle controller and is used to use the ECU component to receive the braking signal output by the vehicle controller and calculate the braking pressure and motor torque based on the braking signal.

[0041] Therefore, the present invention adopts the above-mentioned dual-mode wire control braking method and braking system, which has the following beneficial effects:

[0042] 1. High reliability and redundant design: The two brake-by-wire modules serve as backup for each other. When the active module fails, the standby module can immediately take over, ensuring uninterrupted braking function and avoiding brake failure caused by failure of a single unit.

[0043] 2. Accurate signal acquisition and processing: Dual sensors (angle and force sensors) are used to redundantly collect braking intent. A signal verification mechanism improves the accuracy of input signals, preventing misjudgments caused by single sensor failures and ensuring reliable transmission of braking intent.

[0044] 3. Intelligent flow channel switching and isolation: The brake connector can switch flow channels according to the system status, isolate faulty units, and ensure stable transmission of brake fluid pressure to the caliper, improving the safety and fault tolerance of the brake system and effectively coping with complex working conditions;

[0045] 4. Precise pressure control: The ECU and HCU components work together to achieve rapid and accurate build-up of brake pressure through precise control of motor torque and closed-loop pressure regulation, meeting the requirements of highly dynamic and precise braking response in scenarios such as autonomous driving.

[0046] 6. Flexible system adaptability: The design of independent installation of the wire control brake unit and brake connector enables flexible layout according to the cabin space of different models, enhancing the applicability and scalability of the solution and facilitating its application on various vehicle platforms.

[0047] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a functional block diagram of the braking system of the present invention;

[0049] Figure 2 A circuit diagram of a brake-by-wire module of a braking system of the present invention;

[0050] Figure 3 A schematic structural diagram of a brake-by-wire module of a braking system according to the present invention;

[0051] Figure 4 This is a schematic structural diagram of a brake connector of the brake system of the present invention from one perspective;

[0052] Figure 5 A schematic structural diagram of a brake connector of the brake system of the present invention from another perspective;

[0053] Figure 6 is a cross-sectional view of a pedal assembly of a braking system of the present invention;

[0054] Figure 7 is an outline diagram of the pedal assembly of the braking system of the present invention;

[0055] Figure 8 The figure is a flow chart of a dual-mode wire control braking method of the present invention.

[0056] Reference numerals

[0057] 1. Fluid reservoir; 2. HCU assembly; 3. ECU assembly; 4. Two-position three-way valve; 5. Force sensor; 6. Angle sensor; 7. Pedal arm; 8. Elastic buffer assembly; 9. Mounting shell; 10. Brake pedal. DETAILED DESCRIPTION

[0058] In order to make the purposes, technical solutions and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions.

[0059] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0060] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0061] like Figure 1-Figure 7 A braking system is shown, including a pedal assembly, a vehicle controller electrically connected to the pedal assembly, and a brake-by-wire module electrically connected to the vehicle controller. The brake-by-wire module employs a redundant structure and includes a primary brake-by-wire unit and a redundant brake-by-wire unit. Both the primary brake-by-wire unit and the redundant brake-by-wire unit are connected to the brake caliper via a brake connector. In this embodiment, the brake connector includes a valve body, a FL (front left) inlet, a RR (rear right) inlet, a RL (rear left) inlet, and a FR (front right) inlet located on one side of the valve body, and a FL, RR, RL, and FR outlets located on the other side of the valve body. The FL, RR, RL, and FR inlets are connected to the FL, RR, RL, and FR outlets, respectively, via flow channels located within the valve body. The valve body is provided with a two-position three-way valve 4 for controlling FL, RR, RL and FR respectively, so as to realize the switching between the main brake-by-wire unit and the redundant brake-by-wire unit by using the two-position three-way valve 4 .

[0062] The pedal assembly includes a mounting shell 9 arranged on the firewall of the vehicle and a pedal arm 7, one end of which is rotatably arranged inside the mounting shell 9. The other end of the pedal arm 7 extends out of the mounting shell 9 and is fixedly connected to the brake pedal 10; an angle sensor 6 is provided at the rotating connection between the pedal arm 7 and the mounting shell 9, and a force sensor 5 is provided at the power output end of the pedal arm 7 through an elastic buffer component 8. The force sensor 5 and the angle sensor 6 are both electrically connected to the output end of the vehicle controller. The vehicle controller determines the driver's braking intention and braking force based on the collected values of the force sensor 5 and the angle sensor 6; the force sensor 5 and the angle sensor 6 serve as backups for each other.

[0063] In this embodiment, the elastic buffer component 8 is a spring, a disc spring or a high-rigidity rubber, which is used to increase the pedal rod and reduce braking noise.

[0064] Both the main brake-by-wire unit and the redundant brake-by-wire unit include a fluid reservoir 1, an HCU component 2 connected to the output end of the fluid reservoir 1, and an ECU component 3 electrically connected to the HCU component 2. The ECU component 3 of the main brake-by-wire unit and the ECU component 3 of the redundant brake-by-wire unit communicate with each other to achieve two-way backup; the ECU component 3 is electrically connected to the vehicle controller, and is used to use the ECU component 3 to receive the braking signal output by the vehicle controller, and calculate the braking pressure and motor torque based on the braking signal.

[0065] A dual-mode brake-by-wire method comprises the following steps:

[0066] S1. Determining the driver's braking intention and braking force in a normal driving mode or an automatic driving mode, generating a braking command, and transmitting the control command to a brake-by-wire module;

[0067] In step S1, in normal driving mode, when the angle sensor collects the rotation angle of the pedal arm Or the force sensor synchronously collects the pedaling force When it is greater than 0, it is determined that there is a braking intention, and when the rotation angle is set and pedaling force When the signals are primary and auxiliary respectively, the braking force is calculated using the following formula:

[0068] (1);

[0069] Where, Indicates the travel-braking force coefficient; Indicates the angle-stroke conversion coefficient;

[0070] When setting the pedaling force and rotation angle When the signals are main and auxiliary respectively, the braking force is calculated using the following formula :

[0071] (2);

[0072] Where, Indicates the piston area of the brake master cylinder;

[0073] In autonomous driving mode, the vehicle's front environment is monitored in real time through onboard sensors to identify obstacles or the distance to the vehicle in front. , set the minimum safety distance to ,when When the braking intention is determined, the braking force is calculated using the following formula :

[0074] (3);

[0075] Where, Indicates the vehicle mass; and They respectively represent the real-time vehicle speed and the relative speed between the current vehicle and the obstacle or the vehicle in front.

[0076] S2. The ECU component of the brake-by-wire module obtains the brake pressure according to the received brake command;

[0077] Step S2 specifically includes the following steps:

[0078] S21. Consider the piston area of the brake caliper , calculate brake pressure :

[0079] (4);

[0080] S22. Calculate motor torque based on HCU component efficiency :

[0081] (5);

[0082] Where, Indicates the piston area of the HCU assembly; Indicates the length of the transmission arm of the HCU assembly;

[0083] And add motor speed constraints:

[0084] (6);

[0085] Where, Indicates the maximum speed of the motor; Indicates the maximum linear velocity of the piston of the HCU assembly; Indicates the transmission ratio of the HCU assembly; Indicates the motor rotor radius.

[0086] The S3 and HCU components transfer the brake fluid in the reservoir to the brake calipers to perform braking.

[0087] In step S3, when the main brake-by-wire unit fails, the brake connector is used to switch to the redundant brake-by-wire unit for control and compensate for the pipeline pressure loss:

[0088] (7);

[0089] in,

[0090] (8);

[0091] Where, Indicates compensation pressure; Indicates the pressure value of loss; Indicates the friction coefficient between the brake fluid and the pipeline; Indicates the length of the pipeline; Indicates the pipe diameter; Indicates the density of brake fluid; Indicates brake fluid velocity.

[0092] Preferably, in step S3, the brake fluid pressure of the HCU component is collected in real time and fed back to the ECU component. The ECU component adjusts the motor torque through a PID algorithm according to the fed-back brake fluid pressure to form a closed-loop control.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A dual-mode brake-by-wire method, characterized by: The following steps are involved: S1. Determining the driver's braking intention and braking force in a normal driving mode or an automatic driving mode, generating a braking command, and transmitting the control command to a brake-by-wire module; In step S1, in normal driving mode, when the angle sensor collects the rotation angle of the pedal arm Or the force sensor synchronously collects the pedaling force When it is greater than 0, it is determined that there is a braking intention, and when the rotation angle is set and pedaling force When the signals are primary and auxiliary respectively, the braking force is calculated using the following formula: （1）； Where, Indicates the travel-braking force coefficient; Indicates the angle-stroke conversion coefficient; When setting the pedaling force and rotation angle When the signals are main and auxiliary respectively, the braking force is calculated using the following formula : （2）； Where, Indicates the piston area of the brake master cylinder; In autonomous driving mode, the vehicle's front environment is monitored in real time through onboard sensors to identify obstacles or the distance to the vehicle in front. , set the minimum safety distance to ,when When the braking intention is determined, the braking force is calculated using the following formula : （3）； Where, Indicates the vehicle mass; and Respectively represent the real-time vehicle speed and the relative speed between the current vehicle and the obstacle or the vehicle in front; S2. The ECU component of the brake-by-wire module obtains the brake pressure according to the received brake command; Step S2 specifically includes the following steps: S21. Consider the piston area of the brake caliper , calculate brake pressure : （4）； S22. Calculate motor torque based on HCU component efficiency : （5）； Where, Indicates the piston area of the HCU assembly; Indicates the length of the transmission arm of the HCU assembly; And add motor speed constraints: （6）； Where, Indicates the maximum speed of the motor; Indicates the maximum linear velocity of the piston of the HCU assembly; Indicates the transmission ratio of the HCU assembly; Indicates the motor rotor radius; S3 and HCU components transfer the brake fluid in the reservoir to the brake caliper to perform braking; In step S3, when the main brake-by-wire unit fails, the brake connector is used to switch to the redundant brake-by-wire unit for control and compensate for the pipeline pressure loss: （7）； in, （8）； Where, Indicates compensation pressure; Indicates the pressure value of loss; Indicates the friction coefficient between the brake fluid and the pipeline; Indicates the length of the pipeline; Indicates the pipe diameter; Indicates the density of brake fluid; Indicates brake fluid velocity.

2. The dual-mode brake-by-wire method according to claim 1, characterized in that: In step S3, the brake fluid pressure of the HCU component is collected in real time and fed back to the ECU component. The ECU component adjusts the motor torque through the PID algorithm according to the fed-back brake fluid pressure to form a closed-loop control.

3. A braking system for executing the dual-mode brake-by-wire method of claim 2, comprising a pedal assembly, a vehicle controller electrically connected to the pedal assembly, and a brake-by-wire module electrically connected to the vehicle controller, characterized in that: The brake-by-wire module adopts a redundant structure and includes a main brake-by-wire unit and a redundant brake-by-wire unit. Both the main brake-by-wire unit and the redundant brake-by-wire unit are connected to the brake caliper via a brake connector.

4. A braking system according to claim 3, characterized in that: The pedal assembly includes a mounting housing arranged on the vehicle firewall and a pedal arm with one end rotatably disposed inside the mounting housing, and the other end of the pedal arm extends out of the mounting housing and is fixedly connected to the brake pedal; An angle sensor is provided at the rotational connection between the pedal arm and the mounting housing, and a force sensor is provided at the power output end of the pedal arm via an elastic buffer assembly. Both the force sensor and the angle sensor are electrically connected to the output end of the vehicle controller. The vehicle controller determines the driver's braking intention and braking force based on the collected values of the force sensor and the angle sensor. The force sensor and angle sensor serve as backup for each other.

5. A braking system according to claim 4, characterized in that: The primary brake-by-wire unit and the redundant brake-by-wire unit each include a fluid reservoir, an HCU assembly connected to an output end of the fluid reservoir, and an ECU assembly electrically connected to the HCU assembly. The ECU assembly of the primary brake-by-wire unit and the ECU assembly of the redundant brake-by-wire unit communicate with each other to achieve two-way backup. The ECU component is electrically connected to the vehicle controller and is used to use the ECU component to receive the braking signal output by the vehicle controller and calculate the braking pressure and motor torque based on the braking signal.

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